Adapter assembly including a removable trocar assembly

ABSTRACT

An adapter assembly for connecting a loading unit to a handle assembly is provided. The adapter assembly includes a sleeve, a trocar assembly releasably securable with the sleeve, and a locking mechanism configured to releasably secure the trocar assembly within the sleeve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 16/171,468, filed Oct. 26, 2018, which is a continuation of U.S. patent application Ser. No. 14/865,602, filed Sep. 25, 2015, now U.S. Pat. No. 10,111,684. Each of these entire disclosures are incorporated by reference herein in its entirety.

BACKGROUND Technical Field

The present disclosure relates to reusable surgical stapling devices. More particularly, the present disclosure relates to reusable adapter assemblies including a removable trocar assembly for use with a circular stapler.

Background of Related Art

Surgical devices for applying staples, clips, or other fasteners to tissue are well known. Typically, endoscopic stapling devices include an actuation unit, i.e., a handle assembly for actuating the device and a shaft for endoscopic access, and a tool assembly disposed at a distal end of the shaft. In certain of these devices, the shaft includes an adapter assembly, having a proximal end securable to the handle assembly and a distal end securable to the tool assembly. The adapter assembly may include an extension.

The adapter assembly may be reusable. To facilitate sterilization and cleaning of the adapter assembly, it would be beneficial to have an adapter assembly including a removable trocar assembly.

SUMMARY

An adapter assembly for connecting a loading unit to a handle assembly is provided. The adapter assembly includes a sleeve, a trocar assembly releasably securable with the sleeve, and a locking mechanism configured to releasably secure the trocar assembly within the sleeve. The trocar assembly includes a housing defining first and second locking slots. The locking mechanism includes first and second locking members configured for selective reception within the respective first and second locking slots of the trocar housing.

In embodiments, the first and second locking members are moveable between a first position where the trocar assembly is securely received within the sleeve and a second position where the trocar assembly is removable from within the sleeve. The locking mechanism may include a button member for moving the first and second locking members between the first position and the second position. The first and second locking members may be biased to the first position by respective first and second springs. The first and second locking members may maintain the button member in an outward position when the first and second locking members are in the first position.

In some embodiments, the adapter assembly includes upper and lower band guides. First and second block members may be movably supported on the upper and lower band guides. The adapter assembly may further include inner and outer flexible band assemblies. The upper and lower band guides may each define a longitudinal recess for accommodating the inner and outer flexible band assemblies. The locking mechanism may further include a button member. The button member may be operably secured to the upper band guide. Each of the upper and lower band guides may include a pair of cam posts for operably supporting the first and second locking members.

In one embodiment, the adapter assembly may further include a base, and a handle rotatably secured to the base. A proximal end of the sleeve may be fixedly secured to the handle to permit rotation of the sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with a general description of the disclosure given above, and the detailed description of the embodiments given below, serve to explain the principles of the disclosure, wherein:

FIG. 1 is a perspective view of a surgical stapling device including an handle assembly with an adapter assembly according to one embodiment of the present disclosure;

FIG. 2 is a perspective view of the adapter assembly shown in FIG. 1 with a removable trocar assembly extending from a distal end of the adapter assembly;

FIG. 3 is a perspective view of a drive assembly of the adapter assembly shown in FIG. 1 with components separated;

FIG. 4 is a side perspective view of the removable trocar assembly, a sleeve, and a connector housing of the adapter assembly shown in FIG. 1, with components separated;

FIG. 5 is a side perspective view of a distal end of the adapter assembly shown in FIG. 1, with the sleeve shown in phantom;

FIG. 6 is a perspective view of the removable trocar assembly shown in FIG. 4, with parts separated;

FIG. 7 is a side perspective view of a locking mechanism of the adapter assembly shown in FIG. 1, with parts separated;

FIG. 8 is a cross-sectional perspective view taken along section line 8-8 shown in FIG. 5;

FIG. 9 is a cross-sectional top view taken along section line 9-9 shown in FIG. 8, with first and second locking blocks of the locking mechanism in a locked position;

FIG. 10 is an enlarged view of the indicated area of detail shown in FIG. 9;

FIG. 11 is a cross-sectional end view taken along section line 11-11 shown in FIG. 9;

FIG. 12 is a cross-sectional view taken along section lines 8-8 shown in FIG. 5, with the locking mechanism in a first or locked position;

FIG. 13 is a perspective side view of the removable trocar assembly and the locking mechanism of the adapter assembly shown in FIG. 1, in the locked position;

FIG. 14 is a cross-sectional view taken along respective section lines 8-8 shown in FIG. 5, with the locking mechanism in a second or release position;

FIG. 15 is a perspective side view of the removable trocar assembly and the locking mechanism shown in FIG. 13, in the release position; and

FIG. 16 is a cross-sectional top view taken along section line 9-9 shown in FIG. 8, with first and second locking blocks of the locking mechanism in an unlocked position.

DETAILED DESCRIPTION

Embodiments of the presently disclosed adapter assembly including a removable trocar assembly will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. As is common in the art, the term “proximal” refers to that part or component closer to the user or operator, i.e. surgeon or clinician, while the term “distal” refers to that part or component further away from the user.

Referring initially to FIG. 1, an adapter assembly according to an embodiment of the present disclosure, shown generally as adapter assembly 100, is a component of a surgical stapling device 10. The surgical stapling device 10 further includes a powered handle assembly 20, a loading unit 30, and an anvil assembly 40. Although shown and described with reference to surgical stapling device 10, the aspects of the present disclosure may be modified for use with manual surgical stapling devices having various configurations, and with powered surgical stapling devices having alternative configurations. For a detailed description of an exemplary surgical stapling device, please refer to commonly owned U.S. Pat. No. 9,023,014 (“the '014 patent) and U.S. Pat. Appl. Publ. No. 2012/0253329 (“the '329 application”), the contents of each of which are incorporated by reference herein in their entirety.

With reference to FIG. 2, the adapter assembly 100 includes a proximal portion 102 configured for operable connection to the handle assembly 20 (FIG. 1) and a distal portion 104 configured for operable connection to the loading unit 30 (FIG. 1) and to the anvil assembly 40 (FIG. 1). Although shown and described as forming an integral unit, it is envisioned that the proximal and distal portions 102, 104 may be formed as separate units that are releasably securable to one another.

The adapter assembly 100 will only be described to the extent necessary to fully disclose the aspects of the present disclosure. For a detailed description of an exemplary adapter assembly, please refer to commonly owned U.S. Provisional Pat. Appl. Ser. No. 62/066,518 (“the '518 application”), the content of which is incorporated by reference herein in its entirety.

With continued reference to FIG. 2, the adapter assembly 100 includes an outer sleeve 106, and a connector housing 108 secured to a distal end of the outer sleeve 106. The connector housing 108 is configured to releasably secure an end effector, e.g., the end effector 30 (FIG. 1), to the adapter assembly 100.

Turning briefly to FIG. 3, a drive assembly 110 extends through the outer sleeve 106 (FIG. 2) of the adapter assembly 100, and includes an inner flexible band assembly 112 and an outer flexible band assembly 114. The inner flexible band assembly 112 includes first and second flexible bands 112 a, 112 b, and an inner pusher member 116 connected to the distal ends of the first and second flexible bands 112 a, 112 b. Similarly, the outer flexible band assembly 114 includes first and second flexible bands 114 a, 114 b, and an outer pusher member 118. For a detailed description of the structure and function of the drive assembly 110, please refer to the '518 application, the content of which was previously incorporated herein by reference in its entirety.

With reference now to FIGS. 4 and 5, the adapter assembly 100 further includes a trocar assembly 120 that extends through the actuation assembly 110 (FIG. 5), and a locking mechanism 130 (FIG. 5) that releasably secures the trocar assembly 120 relative to the outer sleeve 106 of the adapter assembly 100. The trocar assembly 120 will only be described to the extent necessary to describe the aspects of the present disclosure. For a detail description of the structure and function of an exemplary trocar assembly, please refer to the '518 application, the content of which was previously incorporated by reference herein in its entirety.

Referring also to FIG. 6, the trocar assembly 120 of the adapter assembly 100 (FIG. 2) includes an outer housing 122, a trocar member 124 slidably disposed within the outer housing 122, and a drive screw 126 operably received within the trocar member 124 for axially moving the trocar member 124 relative to the outer housing 122. More specifically, the trocar member 124 defines a threaded bore 124 a which is dimensioned to receive the drive screw 126. The outer-surface of the drive screw 126 is threaded such that rotation of the drive screw 126 causes longitudinal movement of the trocar member 124 within the outer housing 122 of the trocar assembly 120. A distal end 124 b of trocar member 124 is configured to releasably engage an anvil assembly, e.g., the anvil assembly 40 (FIG. 1). A bearing assembly 128 is mounted to a proximal end of outer housing 122 of trocar assembly 120 for rotatably supporting the drive screw 126 within the outer housing 122 and the trocar member 124. As will be described in further detail below, the outer housing 122 defines first and second locking slots 123 a, 123 b for receiving the respective first and second locking blocks 136, 138 (FIG. 7) of the locking mechanism 130 of the adapter assembly 100.

With particular reference now to FIG. 7, the locking mechanism 130 of the adapter assembly 100 includes upper and lower band guides 132, 134 supported within the outer sleeve 106 (FIG. 5), first and second locking blocks 136, 138 operably supported on each of the upper and lower band guides 132, 134, and a button member 140 slidably secured to the upper band guide 132 for moving the first and second locking blocks 136, 138 relative to each other. As will be described in further detail below, first and second springs 142 a, 142 b extend from within respective first and second locking blocks 136, 138 and bias the locking blocks 136, 138 radially inward.

With continued reference to FIG. 7, the upper band guide 132 of the locking mechanism 130 includes a body portion 144 disposed within the outer sleeve 106 of the adapter assembly 100. The body portion 144 of the upper band guide 132 defines a longitudinal recess 143 for accommodating the first flexible bands 112 a, 114 a of the respective inner and outer flexible band assemblies 112, 114. The body portion 144 of the upper band guide 132 further defines first and second cutouts 145 a, 145 b for operably receiving respective first and second legs 140 a, 140 b of the button member 140 of the locking mechanism 130. First and second button retainer tabs 146 a, 146 b (FIG. 12) extend outwardly from the body portion 144 of the upper band guide 132. In particular, the first button retainer tab 146 a is disposed in the first cutout 145 a of the body portion 144 and the second button retainer tab 146 b is disposed in the second cutout 145 b of the body portion 144.

As will be described in further detail below, the first and second button retainer tabs 146 a, 146 b are received within respective slots 141 a, 141 b of the button member 140 to operably secure the button member 140 to the upper guide band 132. First and second flange portions 148 a, 148 b extend outwardly from the body portion 144 of the upper band guide 132. Each of the first and second flange portions 148 a, 148 b includes a cam post 150 a, 150 b, respectively. As will be described in further detail below, the cam posts 150 a, 150 b of the respective first and second flange portions 148 a, 148 b are received within first and second cam slots 131 a, 131 b and 133 a, 133 b of first and second locking blocks 136, 138. The upper band guide 132 further includes strain gauge retainer portions 152 extending from the body portion 144 for supporting a strain gauge 170 (FIG. 8).

With continued reference to FIG. 7, the lower band guide 134 of the locking mechanism 130 includes a body portion 154 disposed within the outer sleeve 106 (FIG. 1) of the adapter assembly 100. The body portion 154 of the lower band guide 134 defines a longitudinal recess 153 for accommodating the second inner and outer flexible bands 112 b, 114 b (FIG. 3) of the respective inner and outer flexible band assemblies 112, 114 (FIG. 3). The lower band guide 134 includes first and second flange portions 158 a, 158 b that extend outwardly from the body portion 154. The first and second flange portions 158 a, 158 b include first and second cam posts 160 a, 160 b, respectively. The lower band guide 134 further includes strain gauge retainer portions 162 extending from the body portion 144 configured to operate with the strain gauge retainer portions 152 of the upper band guide 132 to support the strain gauge 170 (FIG. 8) about the trocar assembly 120.

As will be described in further detail below, the upper and lower band guides 132, 134 of the locking mechanism 130 are configured such that the first cam posts 150 a, 160 a of the respective upper and lower band guides 132, 134 are received within first cam slots 131 a, 131 b of the first locking block 136 and the second cam posts 150 b, 160 b of the respective upper and lower band guides 132, 134 are received within the second cam slots 133 a, 133 b of the second locking block 138. With additional reference to FIG. 8, the first and second locking blocks 136, 138 of the locking mechanism 130 are movably supported on the upper and lower band guides 132, 134 and are configured to be releasably received within the respective first and second locking slots 123 a, 123 b (FIG. 6) of the trocar housing 122 of the trocar assembly 120.

Each of the first and second locking blocks 136, 138 defines a clearance portions 135 a, 135 b, respectively, to facilitate disengagement of the respective first and second locking blocks 136, 138 from the trocar assembly 120. In particular, the clearance portions 135 a, 135 b are configured such that when the first and second locking blocks 136, 138 are in their second positions (FIGS. 14 and 15), the first and second locking blocks 136, 138 are clear of the outer housing 122 of the trocar assembly 120. As shown in FIG. 14, the clearance portions 135 a, 135 b of the respective first and second locking blocks 136, 138 together define a substantially circular opening with the first and second locking blocks 136, 138 are in their second position. Each of the first and second locking blocks 136, 138 further defines a bore 137 a, 137 b (FIG. 8), respectively, for receiving the first and second springs 142 a, 142 b.

The first and second locking blocks 136, 138 of the locking mechanism 130 are movable between a first, locked position (FIG. 12) in which the outer housing 122 of the trocar assembly 120 is engaged by the first and second locking blocks 136, 138, i.e., portions of the first and second locking blocks 136, 138 are received within respective locking slots 123 a, 123 b of the outer housing 122, and a second, unlocked position (FIG. 14) in which the trocar assembly 120 is moved outwardly from slots 123 a, 123 b such that is removable from between the first and second locking blocks 136, 138 of the locking mechanism 130, i.e., the clearance portions 135 a, 135 b of the respective first and second blocks 136, 138 are aligned with the outer housing 122. The first and second locking blocks 136, 138 are biased inwardly into slots 123 a, 123 b to the first position by the first and second springs 142 a, 142 b. As shown in FIG. 8, the first and second locking blocks 136, 138 are biased upwardly and inwardly towards one another.

With particular reference still to FIG. 7, the button member 140 of the locking mechanism 130 includes first and second legs 140 a, 140 b each defining a slot 141 a, 141 b, respectively. The button member 140 is configured to be received about the upper band guide 132 of the locking mechanism 130 such that the first and second legs 140 a, 140 b of the button member 140 are received within respective first and second cutouts 145 a, 145 b of the upper band guide 132 and the first and second tabs 146 a, 146 b (FIG. 8) of the upper band guide 134 are received within the respective slots 141 a, 141 b.

The operation of the locking mechanism 130 of the adapter assembly 100 will now be described with reference to FIGS. 8-16. Referring initially to FIGS. 8-13, the locking mechanism 130 is shown in the locked configuration, i.e., with the first and second locking blocks 136, 138 in their first position. In particular, the first locking block 136 is supported on the first cam post 150 a of the upper band guide 132 and the first cam post 160 b of the lower band guide 134 and the second locking block 138 is supported on the second cam post 150 b of the upper band guide 132 and the second cam post 160 b of the lower band guide 134. The first and second locking blocks 136, 138 are biased radially inward by respective first and second springs 142 a, 142 b to the first, locked position (FIG. 12).

The trocar assembly 120 of adapter assembly 100 may be provided preloaded within sleeve 106 of the adapter assembly 100, or the trocar assembly 120 may be provided separated from the adapter assembly 100. If provided as a separate component, the trocar assembly 120 is loaded through a distal end of the sleeve 106 of the adapter assembly 100 prior to attaching an end effector, e.g., the end effector 30, to the connector housing 108 of the adapter assembly 100. The trocar assembly 120 is fed into the sleeve 106 of the adapter assembly 100 between the first and second locking blocks 136, 138 to cam the first and second locking blocks 136, 138 outwardly against the bias of springs 142 a, 142 b until alignment of the first and second locking blocks 136, 138 with the first and second locking slots 123 a, 123 b of the outer housing 122. An audible and/or tactile indication may be provided to a user by the locking mechanism 130 as the first and second locking blocks 136, 138 are received with the respective first and second locking slots 123 a, 123 b to indicate that the trocar assembly 120 is securely received within the locking mechanism 130.

During loading of the trocar assembly 120 through the locking mechanism 130, the button member 140 of the locking mechanism 130 may be depressed to move the first and second locking blocks to the second or unlocked position (FIG. 14) to facilitate loading of the trocar assembly 120 between the first and second locking blocks 136, 138, and within the sleeve 106. Alternatively, engagement of the first and second locking blocks 136, 138 by the outer housing 122 of the trocar assembly 120 as the trocar assembly 120 is loaded through the locking mechanism 130 will maintain the first and second locking blocks 136, 138 in their second position until the first and second locking slots 123 a, 123 b of the outer housing 122 align with the respective first and second locking blocks 136, 138. Upon alignment of the first and second locking blocks 136, 138 with the respective first and second locking slots 123 a, 123 b, the first and second locking blocks 136, 138 are biased into the first and second locking slots 123 a, 123 b, respectively.

In embodiments, the outer housing 122 of the trocar assembly 120 includes internal flat portions 125 (FIG. 11) for maintaining rotational alignment of the trocar assembly 120 relative to the locking mechanism 130 to ensure that the first and second locking slots 123 a, 123 b of the trocar assembly 120 are maintained in alignment with the respective first and second locking blocks 136, 138 of the locking mechanism 130.

Engagement of the first and second legs 140 a, 140 b of the button member 140 of the locking mechanism 130 with the respective first and second locking blocks 136, 138 maintains the button member 140 in an outward, non-depressed position. Receipt of the first and second button retainer tabs 146 a, 146 b within respective slots 141 a, 141 bof the first and second leg 140 a, 140, respectively, of button member 140 maintains the button member 140 in engagement with the upper band guide 132 of the locking mechanism 130.

As noted above, the upper and lower band guides 132, 134 each include strain gauge retainer portions 152, 162, respectively, for supporting the strain gauge 170. The trocar assembly 120 of the adapter assembly 100 is received through the strain gauge 170. The strain gauge 170 is configured to measure deflection and/or movement of the trocar assembly 120 during operation of the adapter assembly 100. The first and second flexible bands 112 a, 114 a of the inner and outer flexible band assemblies 112, 114 of the drive assembly 110 are received through the longitudinal recess 143 of the upper band guide 132 and the first and second flexible bands 112 a, 114 b of the inner and outer flexible band assemblies 112, 114 are received through the longitudinal recess 153 of the lower band guide 134.

Once the trocar assembly 120 is loaded with the sleeve 106 and secured therein by the locking mechanism 130, the adapter assembly 100 and the attached handle assembly 20 (FIG. 1), the loading unit 30, and the anvil assembly 40 (FIG. 1) operate in a traditional manner.

Following a surgical stapling procedure using the surgical stapling device 10, the trocar assembly 120 of the adapter assembly 100 is removed from the sleeve 106 of the adapter assembly 100 to facilitate cleaning and/or sterilizing of the adapter assembly 100.

With reference to FIGS. 14-16, the locking mechanism 130 of the adapter assembly 100 is shown with the first and second locking blocks 136, 138 in a second or unlocked position. When the first and second locking blocks 136, 138 are in the second position, the trocar assembly 120 is removable from within the sleeve 106 of the adapter assembly 100.

With particular reference to FIG. 14, the first and second locking blocks 136, 138 are moved to the second position by depressing the button member 140 of the locking mechanism 130 radially inward, as indicated by arrow “A” in FIG. 14. As noted above, the first and second leg portions 140 a, 140 b of the button member 140 engage an upper surface of the respective first and second locking blocks 136, 138. When the button member 140 is depressed, engagement between the first and second leg portions 140 a, 140 b of the button member 140 with the respective first and second locking blocks 136, 138 moves the first and second locking blocks 136, 138 downwardly about the cam posts 150 a, 160 a and 150 b, 160 b against the bias of the first and second springs 142 a, 142 b, respectively. The first locking block 136 rides along the first cam post 150 a, 160 a of the upper and lower band guide 132, 134, respectively. Because of the configuration of the cam slots 131 a, 131 b, the first locking block 136 moves in a radially outward direction, as indicated by arrow “B” to the second position. Similarly, the second locking block 138 rides along the second cam post 150 b, 160 b of the upper and lower band guide 132, 134, respectively. Because of the configuration of the cam slots 133 a, 133 b, the second locking block 138 moves in a radially outward direction, as indicated by arrow “C”, to the second position.

As the first and second locking blocks 136, 138 are moved to their second position, the first and second locking blocks 136, 138 are moved from within the respective first and second locking slots 123 a, 123 b of the trocar assembly 120 and the clearance portions 135 a, 135 b of the respective first and second locking blocks 136, 138 are aligned with the trocar assembly 120. In this manner, the trocar assembly 120 is no longer secured by the locking mechanism 130. The trocar assembly 120 may then be removed from within the sleeve 106 of the adapter assembly 100.

Although the illustrative embodiments of the present disclosure have been described herein with reference to the accompanying drawings, it is to be understood that the disclosure is not limited to those precise embodiments, and that various other changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the disclosure. For example, in any of the embodiments discussed herein, the trocar assembly may form part of a circular surgical stapler that is wholly or partially disposable and such instruments may have a separate adapter or the adapter may be formed as part of the handle assembly. The stapling instrument can be manually operated, powered through an integral or separate motor, or form part of a robotic system. 

1. (canceled)
 2. A locking mechanism for releasably securing a trocar assembly within a sleeve of an adapter assembly, the locking mechanism comprising: a guide assembly including upper and lower guide members supportable within the sleeve of the adapter assembly; a first locking member supported by the upper and lower guide members, the first locking member including an inner surface defining a recess, the first locking member being moveable between a first position where a portion of the inner surface is receivable within a first locking slot of a housing of the trocar assembly to secure the trocar assembly within the sleeve and a second position where the recess of the first locking member aligns with the first locking slot to permit release of the trocar assembly from within the sleeve; and a button member in operable engagement with the first locking member for moving the at least first locking member between the first position and the second position.
 3. The locking mechanism of claim 2, further including a first spring for biasing the first locking member towards the first position.
 4. The locking mechanism of claim 3, wherein the button member is movable between an inward position and an outward position, the first locking member maintaining the button member in the outward position when the first locking member is in the first position.
 5. The locking mechanism of claim 3, wherein the first spring biases the first locking member radially inward and towards the upper guide member.
 6. The locking mechanism of claim 2, wherein the button member is operably secured to the upper guide member.
 7. The locking mechanism of claim 2, further including a second locking member supported on the upper and lower guide members.
 8. The locking mechanism of claim 2, wherein the upper and lower guide members each includes a first post, and the first locking member defines first and second slots, wherein the first post of the upper guide member is received through the first slot and the first post of the lower guide member is received through the second slot.
 9. The locking mechanism of claim 8, further including a second locking member defining first and second slots, wherein the upper guide member includes a second post and the lower guide member includes a second post, wherein the second post of the upper guide member is received through the first slot of the second locking member and the second post of the lower guide member is received through the second slot of the second locking member.
 10. The locking mechanism of claim 8, further including a second spring, wherein the second locking member is movable between a first position and a second position, the second spring being configured to bias the second locking member to the first position.
 11. The locking mechanism of claim 10, wherein the second spring biases the second locking member radially inward and towards the upper guide member.
 12. The locking mechanism of claim 2, wherein the button member is disposed within an opening in the sleeve.
 13. The locking mechanism of claim 2, wherein the upper and lower guide members each defines a recess for receiving bands of a band assembly.
 14. The locking mechanism of claim 2, wherein the button member includes first and second tabs and the upper guide member includes first and second slots, the first and second tabs received within the respective first and second slots to pivotally secure the button member to the upper guide member.
 15. The locking mechanism of claim 2, further including a strain gauge for detecting strain within the adapter assembly.
 16. A locking mechanism for releasably securing a trocar assembly within a sleeve of an adapter assembly, the locking mechanism comprising: a guide assembly supportable within the sleeve of the adapter assembly; a locking member supported by the upper and lower guide members, the locking member including an inner surface defining a recess, the locking member being moveable between a first position where a portion of the inner surface is receivable within a locking slot of a housing of the trocar assembly to secure the trocar assembly within the sleeve and a second position where the recess of the locking member aligns with the locking slot to permit release of the trocar assembly from within the sleeve; a spring member for biasing the locking member toward the first position; and a button member in operable engagement with the first locking member for moving the at least first locking member between the first position and the second position. 